Transshipment at sea, the offloading of catch from a fishing vessel to a refrigerated cargo vessel far from port, obscures the actual source of the catch and is a significant pathway for illegally caught fish to enter the legitimate seafood market. Occurring out of sight and over the horizon, the practice enables other nefarious activity, ranging from smuggling to human trafficking. Increasing the transparency of transshipment could improve fisheries management and reduce human rights abuses.
To address this gap in transparency, SkyTruth and Global Fishing Watch analyzed over 21 billion positional Automatic Information System (AIS) messages from ocean-going vessels between 2012 and 2016, and we identified and tracked an estimated 90 percent of the world’s refrigerated cargo ships (reefers). We mapped 86,490 instances in which these reefers exhibited rendezvous behaviors at sea for long enough to receive a transshipment, events that we call “potential transshipments,” and 5,065 instances where we see a fishing vessel rendezvousing with the reefer, events we call “likely transshipments.” We considered only events that occurred at sea, ignoring transshipments at port, which are generally less of a management challenge.